December 2008. A beetle from the Federated States of Micronesia found on cucumber. The beetle is 4-5 mm long and orange. At first, it was thought to be the pumpkin beetle, Aulacophora simillis, but the pumpkin beetle is twice the size.

Members suggested that it was a flea beetle from the size of the femora, possibly Aphthona bicolorata, which is very common on Guam. It is found there on cucurbits and other crops, but it is not considered to be a serious pest. In Insects of Micronesia, Gressitt reports this beetle being found in Palau, Ulithi, Truk, Saipan, Tinian and Guam.

Note, the Bishop Museum has recently made Insects of Micronesia available online as PDFs at
http://hbs.bishopmuseum.org/pubs-online/iom.html.

The Australian Museum suggested that it is a male alticine – body shape indicates its either Longitarsus or Aphthona. The first metatarsomere (back leg first tarsal segment) is short, therefore, its Aphthona. It fits Aphthona bicolorata in size, colour and sculpture, also distribution (widespread in western Pacific). Samuelson 1973 is the best reference and records it from New Guinea, Solomon Islands, New Hebrides and Micronesia on Euphorbia, and possibly other plants. But A veitchi (widespread in same area, same colour pattern, similar hosts) is only reliably separable by size and genitalia. The size is 2.75-3.80 mm for bicolorata; 1.60-2.45 mm for veitchi.